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Mastozoología neotropical

versão impressa ISSN 0327-9383

Resumo

Many methods of age determination have been used to date. However, most of them require laboratory procedures which are, in general, not available for wildlife managers in the field. In this paper we attempt to standardize the age categories for six mammal species through the analysis of dental wear, dental eruption and body mass. We analyzed 632 skulls, including Mazama nemorivaga (brown brocket deer), Mazama americana (red brocket deer), Tayassu pecari (white-lipped peccary), Pecari tajacu (collared peccary), Cuniculus paca (paca) and Dasyprocta leporina (agouti). Using biological and morphological criteria we define four age categories: young, sub adult, adult and senescent adult. Scores and variables of molar cusp wear and eruption were defined for each age category within each species. We found significant differences in mean weights among age categories for D. leporina (F = 81.1; df = 3; p < 0.05), C. paca (F = 39.0; df = 3; p < 0.05), P. tajacu (F = 24.6; df = 3; p < 0.05) and M. americana (F = 30.6; df = 3; p < 0.05), suggesting that body mass can be a complementary criterion for estimating age. Despite being less quantitative than methods such as those which use deposition of cementum layers, the method described here proved to be an efficient tool for field researchers and managers in the Brazilian Amazon. Although similar methods have already been applied in the study of hunted mammals in the Peruvian and Brazilian Amazon, it is the first time such a method is described in detail and therefore it can be easily used in future works.